A multidisciplinary group has been assembled to make a concerted effort to increase our knowledge of reproductive physiology and reproductive biochemistry. The unit has been constituted by bringing together several smaller, heretofore, more or less independent groups. The disciplines now represented comprise: clinical investigation, biochemistry, neuroanatomy and physiology, neuroendocrinology, animal biology and surgery, endocrine biochemistry, immunochemistry, mathematics and bioengineering. Specific objectives for the immediate future are the understanding of: mechanisms of regulation of the menstrual cycles in humans and primates, mechanisms controlling the secretions of gonadotropins in monkeys and humans, the application of control theory to problems of reproduction, the biosynthesis of the gonadal and adrenal hormones, their rates of secretion, metabolism and finally the biochemistry and physiology of protein hormones as studied with the aid of tritiated peptides. It is hoped that besides increasing our fundamental knowledge about the reproductive processes, the efforts of this unit will lead to new approaches for the treatment of abnormal reproductive function and open the way to novel techniques of contraception.